I'm trying out vMix after a couple of years using a competing product stumbled upon it after I'm presented with the following challenge:

Broadcast a local rugby game in 2 languages. Each language gets a different youtube-channel live event.
On the breaks I need to play some promo mp4 files. The audio from these files need to go out on both channels.

I'm thinking I need to have 2 instances of Flash Media Encoder getting the video from vMix. Each broadcasting to it's own youtube channel.

It's the audio part I'm having difficulties with.

English audio comes in through the PC's mic input.
Portuguese audio comes in through the PC's line input.

I can't just select these inputs in FMLE because it would leave out the audio from the MP4 files I queue into the video.

What are my options here?

Appreciate any advice.